JP4808552B2 - Automotive discharge lamp - Google Patents

Description

  The present invention relates to a discharge lamp used for an automobile headlamp.

  As an example of a discharge lamp used for a headlight of an automobile, for example, there is an invention of JP-T-2004-534363 (hereinafter referred to as Patent Document 1). As described in this document, in the discharge lamp, one end of the arc tube is inserted and held in a socket having a space inside, and conductive wires extending from both ends of the arc tube are formed on the bottom and side portions of the socket. The structure is connected to the connected terminal.

  In addition, in such a discharge lamp for an automobile, a structure in which a conductor on the side terminal connection side is bent inside the socket as in JP-A-2005-166670 (hereinafter referred to as Patent Document 2) is adopted. is there. If this structure is used, when the discharge lamp is used in combination with a reflector, the conductor on the side terminal connection side is close to the arc tube, and the portion of the discharge lamp that is inserted into the reflector is reduced in size. There is an advantage of increasing the degree.

JP-T-2004-534363 JP 2005-166670 A

  In an automotive discharge lamp, a high-pressure pulse of several tens of kV is applied for lighting at the time of starting. In this way, if a high voltage pulse is continuously applied every time the lamp is lit, a phenomenon (hereinafter referred to as abnormal discharge) that discharges at a portion other than between the electrodes may occur during the lifetime. If an abnormal discharge occurs, in the worst case, the lamp will not turn on, which can lead to a serious accident.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an automotive discharge lamp that can suppress the occurrence of abnormal discharge.

In order to achieve the above object, an automotive discharge lamp according to the present invention has an arc tube having first and second conducting wires, and first and second terminals, with one end of the arc tube on the front end side. holds, the first, the second conductor first in an automobile discharge lamp comprising a socket connected to a second terminal, wherein the second conductor is bent inside the socket The socket is made of the same material and is integrally formed so as to be sandwiched between the arc tube and the second conductor and to protrude from the rear end side toward the front end. The arc tube has one end inserted into the inner space of the cylindrical wall, and the distance from the front end of the socket to the bent portion of the second conductor is Y ₁ , corresponding to the end portion inserted into the socket, the first, the second When the length of the pre Symbol arc tube containing no line was _{Y 2,} characterized in that Y 2 -Y ₁ is _{4.0mm ≦ Y 2 -Y 1 ≦ 6.0mm} .

  According to the present invention, the occurrence of abnormal discharge can be suppressed.

  Hereinafter, an automotive discharge lamp according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an overall view showing an automotive discharge lamp according to a first embodiment, and FIG. 2 is an explanatory view of an arc tube.

  The automobile discharge lamp of the present embodiment has a light-emitting tube LB. The arc tube LB has a double tube structure, and an inner tube 1 is disposed inside. The inner tube 1 has an elongated shape, and an elliptical discharge portion 11 is formed at the approximate center of the tube axis. Plate-shaped sealing portions 12a and 12b are formed at both ends of the discharge portion 11, and cylindrical non-sealing portions 13a and 13b are formed at both ends thereof. For such an inner tube 1, a material having heat resistance that can sufficiently withstand high temperatures during lighting and translucency capable of transmitting generated light with as little loss as possible can be used. Specifically, quartz glass, ceramics such as translucent alumina, and the like are suitable.

  Inside the discharge part 11, the center is substantially cylindrical, and tapered discharge spaces 14 are formed at both ends thereof. The volume of the discharge space 14 is desirably 10 μl to 40 μl for a discharge lamp used in an automobile.

  The discharge space 14 is filled with a discharge medium composed of the metal halide 2 and a rare gas. The metal halide 2 is solid at room temperature (25 ° C.) and is composed of halides of sodium, scandium, zinc, and indium. It is most preferable to select iodine having low reactivity among halides to be bonded to these metals. However, the halide to be bonded is not limited to iodine, and bromine, chlorine, or a combination of a plurality of halides may be used.

  As the rare gas, xenon is enclosed. The pressure of xenon is preferably 5 atm or more, more preferably 10 to 15 atm at room temperature. In addition to xenon, neon, argon, krypton, or the like may be used, or a combination thereof may be used.

  Here, the discharge space 14 essentially does not contain mercury. “Essentially free of mercury” means an amount equivalent to no mercury or little sealed even when compared with a conventional mercury-containing discharge lamp, for example, less than 2 mg per ml, Preferably, even if an amount of mercury of 1 mg or less is present, it is acceptable.

Mounts 3a and 3b are sealed inside the sealing portions 12a and 12b.
The mounts 3a and 3b are constituted by metal foils 3a1 and 3b1, electrodes 3a2 and 3b2, coils 3a3 and 3b3, and external lead wires 3a4 and 3b4.

  The metal foils 3a1 and 3b1 are thin metal plates made of, for example, molybdenum.

  The electrodes 3a2, 3b2 are tritated tungsten electrodes obtained by doping tungsten with thorium oxide. The base end side is connected to the end of the metal foil 3a1, 3b1 on the discharge part 11 side by laser welding, and the other end is kept at a predetermined inter-electrode distance in the discharge space 14, and the tip ends of the metal foils 3a1, 3b1 face each other. Are arranged as follows. Here, the “predetermined interelectrode distance” is preferably 5 mm or less for a short arc lamp, and further about 4.2 mm when used for an automobile headlamp. The electrodes 3a2, 3b2 have a shape composed of a large diameter tip portion and a small diameter shaft portion.

  The coils 3a3 and 3b3 are made of, for example, doped tungsten, and are spirally wound around the shaft portions of the electrodes 3a2 and 3b2.

  The external lead wires 3a4 and 3b4 are made of, for example, molybdenum, and are connected to end portions of the metal foils 3a1 and 3b1 on the opposite side to the discharge portion 11 by welding or the like. The other end sides of the external lead wires 3a4 and 3b4 extend to the outside of the sealing portions 12a and 12b along the tube axis.

  In addition, a cylindrical outer tube 4 having an action of blocking ultraviolet rays by adding an oxide such as titanium, cerium, or aluminum to quartz glass is provided outside the hermetic vessel 1 along the tube axis. It is provided concentrically with the container 1. These connections are made by melting both end portions of the outer tube 4 in the cylindrical non-sealing portions 13a, 13b at both ends of the airtight container 1, and the inside is kept airtight. The space between the hermetically sealed airtight container 1 and the outer tube 4 can be filled with, for example, one kind or a mixture of rare gases such as nitrogen, neon, argon, and xenon. A metal band 51 is attached to the outer peripheral surface of the outer tube 4.

  When the inner tube 1 and the outer tube 4 are connected by melting, first and second melting portions 4a and 4b are formed at both ends of the arc tube LB. The first and second melting portions 4a and 4b may be in a melted state in which the respective connection surfaces are not completely mixed as shown in FIG. Also good.

  A socket 6 is connected to the first melting portion 4a side of the arc tube LB configured as described above. In these connections, the metal band 51 is sandwiched between four metal tongue pieces 52 (two are shown in FIG. 1) formed to protrude from the opening side of the socket 6, and the metal band 51 and the tongue piece 52 are further sandwiched. These contact points are performed by laser welding. A bottom terminal 7a and a side terminal 7b are formed on the bottom and side of the socket 6, and the lead wire 3a4 is connected to the bottom terminal 7a by laser welding or the like.

  Here, the structure of the socket 6 will be described in more detail with reference to the explanatory view of the socket of FIG. (A) is the figure which looked at the socket from the front end direction, (b) is the figure which looked at the cross section of Z-Z 'from the arrow direction.

  The socket 6 is made of a PPS resin (polyphenylene sulfide resin) which is a glass fiber reinforced plastic material having excellent heat resistance and moldability, and has a withstand voltage characteristic of about 15 kV with a thickness of about 1.0 mm. A flange 61 is formed on the front end side of the socket 6. The front end side surface of the flange 61 is called a reference surface. A space 62 is formed inside the socket 6. The front end side of the space 62 has a large circular opening at the center of the flange 61, and four concave portions 63 for mounting the tongue pieces 52 are formed at equal intervals along the circumference of the opening portion. Yes. The rear end side of the space 62 penetrates the socket 6 and the bottom terminal 7a is located at the outlet.

  Furthermore, a cylindrical wall 64 is formed in the space 62 so as to protrude from the rear end side toward the front end so as to be positioned between the first melting portion 4a of the arc tube LB and the support wire 3c. The cylindrical wall 64 is desired to have a thickness d of at least 2.0 mm and a height h of 10.0 mm or more in order to maintain a sufficient withstand voltage. The space inside the cylindrical wall 64 is formed to be slightly larger than the diameter of the first melting part 4a.

  In addition to the space 62, the flange 61 is formed with a space 65 whose front end is open. The space 65 is composed of two spaces 66 and 67 having different sizes. The space 67 penetrates the rear end side of the socket 6 and the side terminal 7b is located at the outlet.

  A support wire 3c made of nickel is introduced into the space 65, and one end is connected to the lead wire 3b4 and one end is connected to the side terminal 7b. The support wire 3 c has first and second bent portions 3 c 1 and 3 c 2 in the spaces 66 and 67, respectively, and has a crank-shaped portion in the space 65. An insulating sleeve 8 made of ceramic is attached to the support wire 3c from the lead wire 3b4 parallel to the tube axis to the first bent portion 3c1, and the insulating space made of ceramic is installed in the insertion space 66. The sleeve 8 is inserted, and the periphery of the support wire 3c up to the first bent portion 3c1 is surrounded.

  FIG. 4 is a diagram showing one specification such as dimensions and materials of the automotive discharge lamp according to the present embodiment. The following tests are based on this specification unless otherwise specified.

Discharge vessel 1: quartz glass, discharge space 14 volume = 27 μl, inner diameter = 2.5 mm, outer diameter = 6.2 mm, maximum axial length = 7.8 mm
Discharge medium: sodium iodide, scandium iodide, zinc iodide, indium bromide, metal halide total 0.6 mg, xenon = 12 atm
Electrodes 3a and 3b: Tungsten oxide doped tungsten material, tip diameter = 0.39 mm, base end diameter = 0.30 mm, actual distance between electrodes = 4.35 mm
Socket 6: PPS resin, thickness d = 2.5 mm, height h: 10.5 mm
Positional relationship between socket 6 and arc tube LB, etc .: X ₁ = 4.0 mm, X ₂ = 7.5 mm, X ₃ = 0.8 mm, Y ₁ = 8.0 mm, Y ₂ = 13.3 mm, Y ₃ = 1.2mm
75W at start-up, 35W at steady lighting (bottom terminal 7a is on the high voltage side, side terminal 7b is on the low voltage side), horizontal lighting,
FIG. 5 is a diagram for explaining the presence or absence of abnormal discharge when Y ₂ −Y ₁ is changed. This test was conducted under lighting conditions in which a 20 kV pulse was applied to the lamp while the power was turned on and off repeatedly. The lamp was taken out every 5000 times, and a pulse was applied 5 times. However, if abnormal discharge occurs, it is judged as NG. In the figure, x represents 15000 times or less, Δ represents 15000 times to 20000 times, ○ represents 20000 times to 25000 times, and ◎ represents 25000 times or more. Incidentally, by performing 20000 times the power ON-OFF In this test, the results corresponding to the lit above about 2000 _hours, Y 2 -Y ₁ is 3.0mm or less, abnormal relatively early in the above 7.0mm It can be seen that discharge occurs and abnormal discharge does not occur even after lighting 25000 times from 4.0 mm to 6.0 mm.

Such a result is considered to be because abnormal discharge is likely to occur along a route such as A to C shown in FIG. A and B are cases where the pulse leaks through the cylindrical wall 64, and C is a case where the pulse leaks around the front end side of the socket 6. For abnormal discharge through the paths A and B, it is necessary to sufficiently attenuate the pulse up to the cylindrical wall 64 portion where the pulse easily passes. On the other hand, it is necessary to increase the creepage distance so as not to turn around from the front end side with respect to abnormal discharge caused by the path C. That is, if Y ₂ -Y ₁ is too long or too short, abnormal discharge occurs, and it is desirable that 4.0 mm ≦ Y ₂ −Y ₁ ≦ 6.0 mm in this embodiment. Results were obtained.

FIG. 7 is a diagram for explaining the presence or absence of abnormal discharge when X ₁ + (Y ₂ −Y ₁ ) and the wall thickness d are changed. The test conditions and the presence or absence of occurrence of abnormal discharge are the same as in FIG.

From the results, it can be seen that the thickness d of the cylindrical wall 64 and the occurrence of abnormal discharge are related, and regarding the thickness d, it is easy to generate abnormal discharge as the thickness is thin, and it is difficult to generate abnormal discharge as the thickness is thick. And if the thickness d of the wall of the cylindrical wall 64 is 2.0 mm or more, it tends to be hard to generate abnormal discharge. In addition, with respect to X ₁ + (Y ₂ −Y ₁ ), abnormal discharge is less likely to occur if it is 7.0 mm or more and 11.0 mm or less, and more preferably 8.0 mm or more and 10.0 mm or less. There is.

  Now consider the results of this study.

  The cylindrical wall 64 has an object of preventing a pulse from leaking from the lead wire 3a4 to the support wire 3c when a high voltage pulse is applied to the bottom terminal 7a and the side terminal 7b. However, when the wall thickness d is small despite the formation of the wall, an abnormal discharge has occurred between the lead wire 3a4 and the support wire 3c from the beginning of application of the high voltage pulse, so the wall is thin. In some cases, the function could not be performed sufficiently, and the pulse passed through the wall, leading to abnormal discharge.

  Further, even when the wall thickness is such that abnormal discharge does not occur sufficiently, when a high-pressure pulse is repeatedly applied to the lamp, the cylindrical wall 64 is partially resinated by heat from the arc tube LB and ultraviolet rays during discharge. Degradation occurs. When the deterioration progresses, the deteriorated wall portion cannot maintain sufficient insulation. For this reason, as the number of lighting increases, it becomes easier for the pulse to pass through, and it is considered that the pulse leaked along the path such as A and B in FIG. 6 and an abnormal discharge occurred. If the bent portion is formed on the support wire 3c, the support wire 3c has a protruding portion such as a corner or a curved surface, so that it is easy to stably form the starting point of abnormal discharge, and the bent portion is formed. Abnormal discharge is likely to occur compared to the case where it is not.

From the above consideration, the present inventor combined the structure in which the cylindrical wall 64 has such a thickness that abnormal discharge does not occur at an early stage and attenuates the pulse to such an extent that the pulse is difficult to transmit. We thought that generation could be suppressed over a long period of time. Therefore, in order to prevent early abnormal discharge, the thickness d of the cylindrical wall 64 may be d ≧ 2.0 mm based on the result of a test or the like. Further, in order to attenuate the pulse, X ₁ + (Y ₂ −Y ₁ ) may be set to 7.0 mm or more, preferably 8.0 mm or more based on the test results. However, as in the test of FIG. 5, if X ₁ + (Y ₂ −Y ₁ ) is made too long, there is a possibility that the wall will run from the front end side of the socket 6 and lead to abnormal discharge, so that it is 11.0 mm or less. Preferably, the thickness is within a range of 10.0 mm or less.

Therefore, in the present embodiment, when Y ₁ a distance from the front end of the socket 6 to the first bent portion _3c1, the length of the arc tube LB inserted into the socket 6 and a Y _2, Y ₂ -Y ₁ Is 4.0 mm ≦ Y ₂ −Y ₁ ≦ 6.0 mm, the high-pressure pulse can be sufficiently attenuated, and the occurrence of abnormal discharge due to passing through the wall can be suppressed. Moreover, since the distance which does not go around the cylindrical wall 64 is maintained, generation | occurrence | production of abnormal discharge when not passing through a wall can also be suppressed.

Furthermore, when the thickness of the cylindrical wall 64 is d, d ≧ 2.0 mm, the distance X ₁ between the lead wire 3a4 and the inner surface of the cylindrical wall 64, and from the front end of the socket 6 to the first bent portion 3c1 If Y ₁ is Y ₁ and the length of the arc tube LB inserted into the socket 6 is Y ₂ , then 7.0 mm ≦ X ₁ + (Y ₂ −Y ₁ ) ≦ 11.0 mm The occurrence of abnormal discharge can be suppressed.

  The embodiment of the present invention is not limited to the above, and may be modified as follows, for example.

  In the present embodiment, the support wire 3c is connected to the end of the lead wire 3b4 to connect to the side terminal 7b. However, the same shape as the support wire 3c is integrated with the lead wire 3b4. It may be formed and connected to the side terminal 7b without using the support wire 3c.

  The first and second bent portions 3c1 and 3c2 are not limited to the case where the first and second bent portions 3c1 and 3c2 are bent at a right angle, and an obtuse angle or an acute angle is allowed. However, in order to make it difficult to stably form the starting point of abnormal discharge, it is desirable that the first bent portion 3c1 has an obtuse angle.

1 is an overall view showing an embodiment of an automotive discharge lamp according to a first embodiment of the present invention. Explanatory drawing of an arc tube. Explanatory drawing of a socket. 1 is a specification diagram of dimensions, materials, etc. of an automotive discharge lamp according to the present embodiment. Illustration of the presence or absence of abnormal discharge at the time of changing the Y ₂ -Y _1. Explanatory drawing about the path | route of abnormal discharge generation | occurrence | production. Illustration of the presence or absence of abnormal discharge when _{X 1 + (Y 2 -Y 1} ) and by changing the thickness d of the wall.

Explanation of symbols

LB arc tube 1 inner tube 11 discharge part 12a, 12b sealing part 13a, 13b non-sealing part 14 discharge space 2 metal halide 3a, 3b mount 3a1, 3b1 metal foil 3a2, 3b2 electrode 3a3, 3b3 coil 3a4, 3b4 lead Wire 3c Support wire 3c1, 3c2 First and second bent portions 4 Outer tubes 4a, 4b First and second melted portions 51 Metal band 52 Tongue piece 6 Socket 61 Flange 64 Cylindrical wall 7a Bottom terminal 7b Side terminal 8 Insulation sleeve

Claims (3)

An arc tube having first and second conductors, first and second terminals, one end of the arc tube being held on the front end side, and the first and second conductors being connected to the first, in automotive discharge lamp comprising a socket connected to a second terminal, and
The second conductive wire has a bent portion that is bent inside the socket ;
The socket is made of the same material and has an integral cylindrical wall formed therein so as to be sandwiched between the arc tube and the second conductor and to protrude from the rear end side toward the front end. Have
One end of the arc tube is inserted into the internal space of the cylindrical wall,
Wherein the distance to the bent portion Y _1, corresponding to one end portion inserted into the socket, the length of the first, pre-Symbol arc tube without the second lead of the second lead from the front end of the socket the when the _{Y 2,} automotive discharge lamp, characterized in that Y 2 -Y ₁ is _{4.0mm ≦ Y 2 -Y 1 ≦ 6.0mm} . When the thickness of the cylindrical wall is d, d ≧ 2.0 mm, and the distance X ₁ from the first conductive wire to the inner surface of the cylindrical wall, the bending of the second conductive wire from the front end of the socket Y ₁ a distance to _parts, corresponding to the one end portion inserted into the socket, when the length of the first, pre-Symbol arc tube without the second conductor was Y _2, 7.0 mm ≦ X _The discharge lamp for automobiles according to claim 1, wherein ₁ + (Y ₂ -Y ₁ ) ≤ 11.0 mm.   The discharge lamp for automobiles according to claim 1 or 2, wherein mercury is essentially not contained as a discharge medium.

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